What RV do you have? If it's a big diesel pusher you can get away with not having auxiliary braking on the towed vehicle. Not legally, mind you, but for practicality. So I don't recommend it officially, but if you are willing to live outside of regulations a bit, I don't think it is unsafe at all to flat tow a 4K lb vehicle behind a 40K lb vehicle without auxilary braking. My 40' Country Coach barely knows it's back there, even in panic stops. But if you have a gasser that's teetering on the edge of GCWR already (as most gas coaches seem to), best do it right and figure out some auxiliary braking.
For tow bars, look at the ones that stay attached to the RV when disconnected, and fold out of the way when not towing. The one I use is a Roadmaster Falcon II. Blue Ox makes a similar model. Attaching the tow bar to the Bronco is the next hurdle. If you use a bolt-on tow plate sold by the tow bar company, chances are it will be something that mounts low and robs approach angle on the trail. Much better IMO is attaching to the recovery points on the bumper, if you have them (not the recovery loops that come with the plastic bumpers). The Modular bumper from Ford, and many aftermarket bumpers, have these tabs. On mine, since I had the plastic stock bumper I had to fabricate some recovery tabs to use with it (see video below). I will eventually replace them, and the bumper, with an aftermarket bumper with built-in tabs. If you have the plastic bumper you don't actually need to fabricate the tabs yourself as fellow SCB member Oscar Espinoza builds and sells some that are similar to the ones I made. You'll still need to have adapters for the tow bar to attach to the recovery tabs.
Last thing to figure out is lighting. So far all I've done is use some drag lights, which are a PITA to set up each time. I will be tapping in to the Bronco's wiring at some point though, so I can just use the Bronco taillights, and hook it up with an umbilical. So far I haven't seen an easy, no-splice plug and play umbilical setup for the Bronco yet (Mopar offers one for flat-towing Jeeps), so I'll probably end up using a universal kit.
I own a car trailer, and I used to haul our Early Broncos on it, but even with those I much prefer flat towing. If you already have a car trailer, go ahead and use it until you get the flat tow bits sorted out. But you'll find out it's SO much easier and convenient to flat tow. Especially with the new 6G Broncos, where you don't have to worry about disconnecting the rear driveshaft on long hauls.
Our videos on flat towing - On fabricating the tow tabs (you won't need to do this):
On hooking up and putting the Bronco in Toad Mode:
Good luck!